Monday brings another such shindig from the Obama administration, this one its first-ever “Energy Datapalooza.” Hosted by Energy Secretary Steven Chu and U.S. Chief Technology Officer Todd Park and featuring about 150 entrepreneurs, software developers, policymakers and energy experts, the event is meant to showcase ways to use freely available data -- including government data -- to “advance a secure and clean energy future.”

To help out, government and private partners will be putting out new datasets, application programming interfaces (APIs), and the like. It’s all part of DOE’s Energy Data Initiative, which is modeled on similar efforts to open publicly available data to innovation in healthcare and public safety.

So what’s on the menu this time around? I spoke to a few companies launching new platforms and services at Monday’s event that gave a sense of the range of applications that open energy data can be used in, from the individual consumer to the macroeconomic level. Take a look:

WattzOn. Launched in 2009 by Twitter Senior Engineering Director Raffi Krikorian and MacArthur “genius” grant winner Saul Griffith, WattzOn started out as a free online tool to help individuals calculate their energy and carbon footprint by entering in their personal data (size of home, commute habits, etc.).

So far, the Mountain View, Calif.-based startup has gotten about 400,000 people to log into its website and check their green credentials against each other and look at averages calculated to deliver localized, personalized tips for saving energy, co-founder Steven Ashby told me in an interview last week.

At the same time, it’s been delving into multiple sources of data to add tools to its core platform, including more than 100 utilities that provide links to customer energy data, he said. It’s also working with military housing contractor Balfour Beatty, the city of San Jose and other business partners, he added.

On Monday, WattzOn launched its latest tool: an “appliance advisor” to help homeowners compare and contrast the energy and environmental costs of thousands of different makes, models and ages of refrigerators. WattzOn uses reams of data from EPA, DOE, the Federal Trade Commission and other official sources, as well as data from other sources, to estimate each fridge’s total cost of ownership, including lifetime energy costs, using regional and national electricity rate data, he said.

There are about 150 million refrigerators in the United States, accounting for about $19.2 billion in annual energy spending, according to 2009 DOE data. More than 45 million of those refrigerators are more than a decade old, which means they were built with old, less-efficient technology that’s only gotten less efficient as it ages, Ashby said.

Indeed, in some cases the cost of keeping that old fridge plugged in for another 10 years can add up to more than the cost of buying a newer model and running it for the same period of time, he said. WattzOn is hoping that its calculator can help lots more homeowners realize that and convince them to invest in a new fridge, saving money and power over the long haul.

The company, which hasn’t disclosed how much private funding it has raised, is planning future advisors for air conditioners, televisions and other household appliances, Ashby said. To make money, it’s looking at white-labeling the platform for appliance makers and retailers wanting to connect potential buyers with up-to-date, accurate energy information, he said.

DataMarket. This Icelandic startup, founded in 2008, has been spending the past four years or so building a platform that collects data from some of the world’s central energy intelligence sources and normalizes it for consumption by subscribers.

Founder and CEO Hjalmar Gislason walked me through a demo of the platform, officially launched on Monday, and showed me how it can take simple queries -- say, “jet fuel emissions,” or “Libyan oil production,” to take a few examples -- and deliver reams of data from sources like the DOE’s Energy Information Administration (EIA), National Renewable Energy Laboratory (NREL) and other national labs, along with the United Nations, the World Bank, BP’s Energy Outlook and EuroNext, to name some key sources.

From there, users can click through to collect and organize data into charts and other graphical displays, as well as cross-reference similar data from different sources -- say, overlay Nigeria and Norway’s oil production to Libya’s, or compare aviation against other industries in terms of global CO2 emissions. DataMarket continually updates its incoming data, which means that users could embed changes in data in their charts and have them updates as time goes by, he said.

In short, it sounds like the energy reporter’s dream tool -- and for the next three weeks or so, DataMarket is making it available on a trial basis. After that, it’s going to start charging subscription fees in the thousands of dollars range, Gislason said, though he wouldn’t reveal specific pricing figures.